DOPPS is known for its hefty volume of research in nephrology outcomes -- it's generated more than 170 studies -- and has given researchers a comparative perspective with its collection of both U.S. and international data.

Port was also the deputy director of the U.S. Renal Data System (USRDS) from 1988 to 1999, and is an emeritus professor of nephrology and epidemiology at the University of Michigan.

At this year's National Kidney Foundation meeting, Port was presented with the David M. Hume Memorial Award, given to a distinguished scientist-clinician in kidney and urologic diseases. He spoke with MedPage Today about changes in dialysis practice over time, upcoming trends in dialysis management, and having DOPPS and USRDS back under one roof. Here's the edited transcript of that conversation.

What key projects are you involved with now at Arbor Research?

I've been involved in various projects, including the transplant registry and some Centers for Medicare and Medicaid Services (CMS) demonstration projects. My activity now focuses on DOPPS projects, and there are multiple. As of this year, we've now expanded to peritoneal dialysis with PDOPPS, and now we have the chronic kidney disease (CKD) study, or CKDopps, to learn about the progression of CKD and the transition to dialysis.

What has been the most valuable research to come out of DOPPS?

The main goal is to correlate practice with outcomes, so we have groups of patients in dialysis units who are undergoing certain practices, and we see big differences in treatment from dialysis unit to dialysis unit. We use a random selection of dialysis units in order to have a mix of practices.

In terms of outcomes, we look at the management of anemia, phosphorus, the prescribing of dialysis, what kind of dialysis, how many hours should we be dializing. We are clearly finding that longer treatment sessions are associated with better outcomes, including lower mortality and fewer hospitalizations. We've also found that quality of life is very important for outcomes, and that depression is common and associated with higher mortality. We've also seen that for patients who have a slower recovery after dialysis, who feel drained and washed out, their quality of life is poorer and their mortality is higher.

Vascular access is also a key issue. We just reported here at this meeting that the U.S. is actually behind other countries regarding vascular access.

DOPPS is international, so you can get a good perspective on U.S. outcomes.

Yes. That's how it was first created, because we had compared registries among Europe, Japan, and the U.S. Renal Data System (USRDS), and found that the U.S. had worse outcomes than other regions. People said, "Well, this is obviously because we have sicker and older patients." We capture every death and other registries may be voluntary, and if they don't report the deaths they have a lower mortality, of course.

So that's why we formed DOPPS, to make this international comparison. And we found that indeed the U.S. has worse outcomes than Europe and Japan. The newest finding is that if we had the same vascular access as in Europe, we'd have the same outcomes. Now we have an explanation.

There have been lots of changes in dialysis management recently, with bundling and now a trend toward peritoneal and home dialysis. How have those been reflected in DOPPS data?

We've had many changes over the last 15 years. We have reported on the trends by country and it's been quite fascinating. For the U.S. bundle, we have a special project called DOPPS Practice Monitor, which uses web-based data collection. At the end of this month will be reporting through December 2013, which is very recent data in terms of trends.

Everyone expected with the bundle that anemia control would be markedly worse, and hemoglobin would fall because doctors would no longer prescribe epoetin the way they should or treat anemia the way they should. But we found there was no such effect -- until 5 months later when the FDA changed the range for ideal hemoglobin and said there's no bottom number for that range. Suddenly, hemoglobin did decrease in the U.S., but it was because of the label changes for epoetin and the FDA rule that affected practice, and not payment, as was expected.

Do you think peritoneal and home dialysis will be a growing trend?

It was the expectation that if the payment was bundled, some dialysis centers would be likely to close because of reimbursement being so tight and that patients would be shifted to peritoneal or home dialysis, and that is in fact being observed now.

Since the bundle, there has been an increase of more than 10%, perhaps about 20%, in the percentage of patients on peritoneal dialysis compared with before -- from about 9% to 11%, and it may rise further. Home hemodialysis is on the increase but the numbers are still so low that it's difficult to study practices.

What countries are leading the way in peritoneal dialysis at this point?

We have Canada, the U.K., and Australia in PDOPPS, and they are leading the way. So is Mexico, and they are interested in joining too, but it's a matter of having funds. Mexico used to have 80% of patients on peritoneal dialysis. Now the trend is toward more hemodialysis, but they have much more experience than any other part of the world.

Arbor Research is getting the USRDS back. What are the advantages to having DOPPS and USRDS under one roof?

It's quite gratifying to see USRDS come back because we are the ones who initiated that. Philip Held, PhD, and myself started USRDS and ran it for 11 years. It's in the process of coming to Michigan, and it's going to be located at the University of Michigan, subcontracted to Arbor Research, which is a nonprofit outside of the university but with lots of links with collaborators around the country and world.

The connection with DOPPS is going to be advantageous because of the experience we have in looking at practices. Instead of looking at 130 practices in the U.S. in DOPPS, we'll have 5,000 practices we can look at.

DOPPS allows us to collect more detail than the USRDS has been able to collect. We have a lot more information on lab values, medication use, dosages, and quality-of-life issues ... so it's our goal to look at practices again as nobody else has done with U.S. data.

The USRDS has also changed over the years since we've had it. CKD is now included as part of the USRDS annual report, and acute kidney injury is also part of it. We're eager to continue this monitoring, especially since we're doing CKDopps.

When you and your collaborators started Arbor Research -- it was known as URREA then -- the USRDS already existed. Why make another database?

It's a fascinating history. The university structure was too complicated to do an international study, so we formed this company last minute in order to have an international study. Since the USRDS had shown that dialysis mortality was higher in the U.S. than elsewhere, we proposed to do a study retrospectively because we needed to have uniform data collection of mortality and clinical data. So that's how DOPPS was born, and it has now grown much bigger, to 90 employees.

I think our success is due to the collaboration we have, with those employees and with several connections with the University of Michigan and other colleagues around the country and world. We have a fabulous staff of programmers, biostatisticians, and analysts who make it successful and feasible. So we expect this collaboration is going to make all of our studies stronger, in particular with USRDS coming home to Michigan.

What would be the closest model to the DOPPS database?

Some say DOPPS is the 'Framingham' of dialysis. There are several other bigger research companies around the U.S., like the RAND Corporation and the Urban Institute, but our focus has been on kidney disease and transplant, and now we're branching out to other areas of chronic disease. We have a famous diabetologist working with us, and we're even going into a glaucoma study.

There are all kinds of things we can do because the ArborLink system allows us to do electronic data collection. We provide the software framework, and we're doing this in 20 different countries for DOPPS, so doctors in Russia, Turkey, and China can enter data that is usable for quick turnaround research analysis. Our programmers make it very easy for any data collection to be moved into research files.

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